Light-dependent roles of the G-protein ? subunit GNA1 of <em>Hypocrea jecorina</em> (anamorph <em>Trichoderma reesei</em>) [electronic resource]
Background: The filamentous ascomycete Hypocrea jecorina (anamorph Trichoderma reesei) is primarily known for its efficient enzymatic machinery that it utilizes to decompose cellulosic substrates. Nevertheless, the nature and transmission of the signals initiating and modulating this machinery are l...
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| Format: | Electronic eBook |
| Language: | English |
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Washington, D.C. : Oak Ridge, Tenn. :
United States. Department of Energy. Office of Science ; Distributed by the Office of Scientific and Technical Information, U.S. Department of Energy,
2009.
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| Summary: | Background: The filamentous ascomycete Hypocrea jecorina (anamorph Trichoderma reesei) is primarily known for its efficient enzymatic machinery that it utilizes to decompose cellulosic substrates. Nevertheless, the nature and transmission of the signals initiating and modulating this machinery are largely unknown. Heterotrimeric G-protein signaling represents one of the best studied signal transduction pathways in fungi. Results: Analysis of the regulatory targets of the G-protein ? subunit GNA1 in H. jecorina revealed a carbon source and light-dependent role in signal transduction. Deletion of gna1 led to significantly decreased biomass formation in darkness in submersed culture but had only minor effects on morphology and hyphal apical extension rates on solid medium. Cellulase gene transcription was abolished in ?gna1 on cellulose in light and enhanced in darkness. However, analysis of strains expressing a constitutively activated GNA1 revealed that GNA1 does not transmit the essential inducing signal. Instead, it relates a modulating signal with light-dependent significance, since induction still required the presence of an inducer. We show that regulation of transcription and activity of GNA1 involves a carbon source-dependent feedback cycle. Additionally we found a function of GNA1 in hydrophobin regulation as well as effects on conidiation and tolerance of osmotic and oxidative stress. Conclusion: We conclude that GNA1 transmits a signal the physiological relevance of which is dependent on both the carbon source as well as the light status. The widespread consequences of mutations in GNA1 indicate a broad function of this G? subunit in appropriation of intracellular resources to environmental (especially nutritional) conditions. |
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| Item Description: | Published through Scitech Connect. 09/03/2009. "Journal ID: ISSN 1741-7007." "Other: PII: 1741-7007-7-58." Seibel, Christian ; Gremel, Gabriela ; do Nascimento Silva, Roberto ; Schuster, Andr ̌; Kubicek, Christian P. ; Schmoll, Monika ; |
| Physical Description: | Size: Article No. 58 : digital, PDF file. |